DIY Network

Wood Finishes: Dyes and Coloring Agents From "Wood Works" episode WWK-504

In this segment, woodworking expert and Wood Works host David Marks talks about dyes and coloring agents in relation to wood finishes.

Safety Alert: Always wear protective gloves, and ensure adequate ventilation, when working with wood stains, solvents and other toxic solutions.

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	Figure A
	Figure B
	Figure C
	Figure D
	Figure E
	Figure F
	Figure G
	Figure H

Finish Terms and Techniques

Coloring agents include stains and dyes and serve to amplify the natural color of the grain.

Finishing coats include oils, shellacs, varnishes, urethanes and lacquers. They seal in and enhance the color as well as protect the wood.

• Coloring agents are most frequently applied directly to raw wood in order to darken or alter the color. Stains may be oil-, water- or alcohol-based. They contain pigments -- finely ground colored particles that stick in the pores, scratches and texture of the wood grain. Stains resist fading, and are typically ideal for furniture pieces that are likely to get a lot of exposure to the sun.

• Stains can be applied with a brush (figure A), a lint-free cloth, or they may be sprayed on. After applying a stain, wipe off the excess. The longer you leave the stain on before wiping, the more it penetrates into the wood -- up to a point. As you apply additional coats, the color tone will become deeper and richer.

• Unlike stains dyes soak into the fiber of the wood without leaving any material on the surface. This allows the grain to show through. Dyes are made up of microscopic colored particles (figure B) that are dissolved in solvents. When added to the wood, dyes can produce bright, clear colors. As seen in the samples (figure C), some dyes are made to look like they occurred naturally, while others are made to dramatically color the wood.

• Aniline dyes come in powdered form and are mixed with water. They are commonly used to color domestic woods. They may fade over time, so they are best used on pieces that won't be exposed to bright or direct light.

• Alcohol-soluble dyes are non-grain-raising dyes that dry fast and produce clear colors (figure D). Since these dyes dry so quickly, it's important to take that fact into consideration when applying them in order to avoid lap-marks. Color-fastness can also be an issue with these dyes.

• Metalized acid dyes are known for their permanence (i.e., color-fastness) and their brilliance. They are water- or alcohol-based and come in a variety of colors such as black, red, yellow, blue and brown. Ebonizing is a technique for using a metalized acid dye to make an inexpensive piece of hardwood look like ebony. This technique was used in an earlier Wood Works episode to make the maple frame of a three-screen panel look like expensive ebony (figure E).

• Another chemical used to color wood is aqua ammonia, and the technique is known as fuming the wood. The fumes of the ammonia react with the tannic acids that occur naturally in the wood to create a great finish. Fuming a piece made from quarter-sawn white oak in a tent made from plastic sheeting and tape (figure F) produces the effect of turning the wood a rich gold and brings out the medullary ray-fleck pattern of this wood (figure G).

• Other chemicals such as potassium dichromate and wood bleaches alter the color or tone of wood through chemical reactions. Potassium dichromate is one of David Marks's personal favorites, and is most frequently used on mahogany and cherry. As seen in the sample board (figure H) the color of the wood can be darkened incrementally by adding more coats.

• Finally, there is one technique for altering the color of some woods that doesn't cost a thing. Cherry, for example, can be turned from a yellow-gold to a reddish tone by simply exposing it to direct sun. The technique also works well with mahogany and a few other woods. Place the piece in direct sunlight, and be sure to rotate it so that each side gets a similar amount of exposure.
  

In the segment that follows, David Marks discusses glossy finishes and clear-coat treatments such as shellacs, lacquers and the ever-popular tung-oil finish.

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